New efficiency records for stable dye-sensitized solar cells with low-volatility and ionic liquid electrolytes

Abstract

We report a high molar extinction coefficient heteroleptic polypyridyl ruthenium sensitizer, featuring an electron-rich 3,4-ethylenedioxythiophene unit in its ancillary ligand. A nanocrystalline titania film stained with this sensitizer shows an improved optical absorption, which is highly desirable for practical dye-sensitized solar cells with a thin photoactive layer, facilitating the efficient charge collection. In conjunction with low-volatility and solvent-free electrolytes, we achieved 9.6-10.0% and 8.5-9.1% efficiencies under the air-mass 1.5 global solar illumination. These dye-sensitized solar cells retain over 90% of the initial performance after 1000 h full sunlight soaking at 60°C. © 2008 American Chemical Society.